I'm pretty-sure TCPView only shows the open connections that originate or terminate on the local computer.
A proxy server that falls between the 2 suggested would be Wingate (
http://wingate.com/purchase/wingate/purchase.php) - you would need at least the Pro version to control their bandwidth - see the 'different features' link there for the differences between versions. (ISA is about $1500 + $20 per user; Squid Cache is free - GNU GPL.)
NTop is also GNU GPL for the linux version, but for windows you either have to pay for a copy (they call it a donation) or compile the source yourself (though the link indicates it's a GZip file -
http://internap.dl.sourceforge.net/sourceforge/ntop/ntop-3.3.7.tar.gz - what actually downloads is a tarball, so get a copy of 7zip while you're at SourceForge if you don't have WinRAR) i.e. you'll need an ANSI C compiler and standard libraries to run it on a win32 box.
Then again, you didn't really say what platform you're using so the windows programs might not help you at all. :-)